This invention relates to a lock apparatus and more particularly to an electronically operated lock and key capable of accommodating a plurality of different control combinations.
Essentially, the most basic security system constitutes a simple lock and key of which there are a tremendous variety of devices and types. Accordingly, the prior art is replete with a large number of patents directed towards electronic lock and key assemblies. The advantage of electronic locks over their mechanical counterparts are relatively obvious in that such assemblies can offer greater protection in guarding against unauthorized entry, key duplication or "lock picking".
The prior art envisions various schemes, most of which provide a control electronic assembly which upon activation by a proper combination or code, operates a solenoid or a controlled mechanical or electromechanical latch. The control assemblies of such electronic locks employ various electrical and magnetic coding schemes such as pulse codes, binary codes, selective frequency determination and others to determine correlation between a predetermined condition as manifested by a particular key or credit card arrangement.
A major disadvantage of many of the prior art devices is that the control unit exhibits a fixed response and therefore can be operated by only a single coded key. In order to implement a change in the key arrangement, one has to rewire, change components or perform other operations such as reprogramming which thereby requires additional equipment and is relatively difficult and expensive to implement. Still other prior art systems cannot, without extensive redesign, accommodate a plurality of different key in a simple and reliable manner.
The ability to rapidly and efficiently change a combination of a lock to enable access by means of any one of a plurality of keys is an important feature in certain business activities such as motels, hotels, vaults and so on. In the operation of such systems which cater to guests or transient trade, keys are exchanged thousands of times a year. Inevitably, such keys are stolen, lost or misplaced and under conventional sytems, an unauthorized person possessing such a key would have direct access to the premises. This, of course, accounts for huge losses by such establishments concerning stolen property and so on.
Many other applications will become apparent to those familiar with the art once a reliable and efficient electronic key and lock assembly are devised to enable the use of such a system in various and diverse applications.
It is therefore advantageous to provide a key and lock assembly which would be capable of rapid and efficient operation at a relatively modest cost, while further providing the ability to simply and reliably alter the combination as desired without the use of external or additional equipment. These aspects are particularly necessary to eliminate the problem of unauthorized access as will be described subsequently.